우리 커피 마실까?

The line, explained

It is late at the office, everyone else has gone home, and two coworkers who have been circling each other for six episodes are still at their desks. One of them finally stands up and says, a little too casually: 우리 커피 마실까? Shall we get some coffee? Nobody actually wants the coffee. That is what makes it such a good line, and such a good way to learn -(으)ㄹ까?.

우리 means we or us. Koreans use it far more than English speakers use 'we', even saying 우리 엄마 (literally our mom) for my mom. Here it sets up a shared plan: not you or me, but us. Starting a suggestion with 우리 instantly makes it feel friendly and inclusive, which is exactly what someone nervous about asking would want.

커피 is coffee, borrowed from English. Since Korean has no f sound, it uses ㅍ, a breathy p, which is why it is keo-pi. Coffee culture in Korea is huge: iced americano, often called 아아, is practically a national drink, ordered even in winter. So inviting someone for coffee is the most ordinary, low-pressure offer there is, the perfect cover for something more.

마실까 is 마시다, to drink, with the ending ㄹ까. Because the stem 마시 ends in a vowel, you add ㄹ까 directly. If the stem ended in a consonant, you would add 을까 instead, as in 먹을까? (shall we eat?). The ending asks for the other person's opinion rather than deciding for them, so it sounds tentative and considerate. Your voice rises at the end, like a question.

With 내가 in front, the same ending offers help: 내가 할까? means shall I do it? Without anyone, it can be a thought to yourself, like I wonder. The replies are easy: 좋아 (sounds good) or 그래 (okay, sure). Try swapping the drink in this line: 우리 차 마실까? means shall we have tea, and 우리 맥주 마실까? means shall we grab a beer.